Dispelling nutrition myths, ranting, and occasionally, raving

Tag Archives: research

Recently there was a lot of criticism of a NYT article about what’s making us fat that was really about what diets might make mice fat. Along the same lines is this research from the University of Missouri that found soy diets might increase women’s bone strength.

The study was not on actual human women though, of course. No, this study’s participants were rats. These rats are apparently a good proxy for human women because they are selectively bred to have low fitness levels and, “average American women are relatively inactive both before, and especially after, menopause”. Essentially, both American women (particularly older women) and these rats are lazy so they’re totally interchangeable when it comes to research. As it’s much harder to get women to adhere to specific diets, and there are far more variable to control for and ethical considerations when it comes to human experiments, it just makes sense to use rats.

So, these rats were divided into two groups: one group was fed a corn-based diet (you know, just like the average post-menopausal American woman eats) and the other was fed a soy-based diet. The results showed that: “the tibia bones of the rats that were fed soy were stronger compared to the rats who were fed the corn-based diet, regardless of ovarian hormone status”. Leading to the conclusion that: “Bottom line, this study showed that women might improve bone strength by adding some soy-based whole foods to their diet”.

To recap: rats were fed either corn-based rat food or soy-based rat food. The rats fed the soy-based rat food were found to have stronger leg bones. Therefore, human women can increase their bone strength by eating more soy.

This is ridiculous. We are not rats. We do not live the same lives as laboratory rats. We are not all sedentary. We do not eat the same food as laboratory rats. It is a huge leap to say that this study in rats shows that consumption of soy by women can lead to stronger bones. We are not eating a homogenous diet of corn-based rat food. The forms of soy we consume as humans are very different from that in rat food (e.g. tofu, soy beverage, tempeh, edamame, TVP).

Perhaps soy-based foods can increase bone strength in humans but this study doesn’t tell us that. This study tells us that this breed of rat has stronger bones when fed a soy-based diet than when fed a corn-based diet.

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Today I just want to rant a little bit about the patriarchy and research, particularly in relation to mothers and pregnant women. You’ve likely all heard about the difference between men and women when it comes to heart attacks, leading to missed diagnoses in many women, and how most drug trials are done using men so that we have very little evidence regarding the efficacy and side effects of many medications on women across their lifespan.

Then you see results of studies like this one which, despite the cognitive effects of alcohol consumed during breastfeeding no longer being evident when children are 10 years of age, provides the message that breastfeeding women should not consume alcohol. This despite the fact that alcohol is removed from breastmilk at the same rate as it is from the bloodstream. This means that while pumping and dumping is an ineffective measure to prevent infants from consuming alcohol via breastmilk that mothers can still safely consume alcohol and breastfeed provided they allow for adequate time for alcohol to clear from the milk. If you’re a breastfeeding mum, you can use this table to determine how long you’ll need to wait after drinking before you can breastfeed your baby (unfortunately, it might be longer than you would think).

Women who are of childbearing age are often told not to consume alcohol at all. Just on the off chance that they might get knocked up and damage the fetus before they realize that they’re pregnant. Women who are pregnant should definitely never consume any alcohol at all because their baby might end up suffering the effects of Fetal Alcohol Spectrum Disorder (FASD). And yet, many perfectly healthy babies are born to women who consume alcohol during pregnancy, indicating that there is likely a window (or windows) during which a certain amount of alcohol may be consumed without affecting the development of the fetus.

Pregnant women are shamed for drinking coffee, and some have even been refused coffee by baristas (and they say dietitians are the food police!). This despite the fact that pregnant women can safely consume up to 300 mg of caffeine a day (about the amount you’d get from a grande coffee). And the fact that the research on caffeine consumption during pregnancy is mixed.

Naturally we want to exhibit an abundance of caution when the health of the woman and the fetus/infant are potentially at risk. However, I bet that if men were the ones giving birth that we would know exactly how much of all these things could be safely consumed during pregnancy and breastfeeding and the precise windows during which they needed to be avoided. But because (cis) men don’t give birth or breastfeed but they generally conduct most of the scientific research we are told to err on the side of caution. I mean what do they care if we can’t have a beer for 30 or so years because we might get pregnant at some point during that time, or enjoy some lovely brie because there is a teensy risk that we might get listeriosis and miscarry. As long as we are protecting their offspring that’s all that matters. And if a woman dares to defy all of the dietary restrictions placed on her during pregnancy societal shaming will cause her to toe the line. After all, questioning these restrictions shows that you are an unfit mother and selfishly putting your enjoyment of bruschetta ahead of your own child for whom you should be enthusiastically giving up everything for while your husband is out drinking with his buddies.

Please note: I am not suggesting that women who are pregnant reject all of this dietary advice. There are very real risks to consuming these foods and beverages during pregnancy. I am however suggesting that we reject the unquestioning acceptance of these restrictions because you know that if men were the ones getting pregnant there would already be a body of research into precisely what could be consumed when.

One thing that struck me right away was that this study was done with adults, no infants or toddlers, or children of any age were involved in the research. Adult participants were provided with puréed vegetables (broccoli, kale, and spinach) with varying concentrations of added sugar. They were asked to rate them on various attributes, and most importantly, they were asked to indicate whether or not they liked or disliked each sample. I was surprised that the conclusion would be drawn that adding sugar to green vegetables is a reasonable means to encourage infants to eat them (I’m saying infants because these were puréed veggies and as such are really only suitable for babies just starting to eat solid foods) based on ratings by adults. After all, adults have very different palates than infants and have very different relationships with food that have been shaped over decades. To me it seems inappropriate to conclude that because adults preferred sugar sweetened veggies that infants will as well. The authors themselves also state that, “It should be noted that infants and toddlers are also not merely small adults”. However, they also use the analogy of adults beginning coffee consumption with added sugar and gradually weaning off the sugar as justification for proposing adding sugar to vegetables when the World Health Organization, among many other bodies, is currently encouraging reduced consumption of added sugars.

The second thing I wondered about was precisely how much sugar was added to each serving of vegetables. The news article, and much of the journal article, references 1% and 2% concentrations but what did that translate to in teaspoons or grams? It sounds pretty innocuous, right? 1% or 2% is hardly anything. Well, in actuality the 1% was equivalent to the addition of 1/2 teaspoon per serving and the 2% was equivalent to 1 teaspoon per serving. Not an insignificant amount when you’re talking about toddlers who are generally only consuming a tablespoon or two of a food in a serving. Interestingly, the researchers asked parents how comfortable they would be offering their babies vegetables with added sugar in amounts of 8 calories, 16 calories, 1/2 teaspoon, or 1 teaspoon. The 8 calories = 1/2 teaspoon = 1% concentration. The 16 calories = 1 teaspoon = 2% concentration. Essentially asking: how can we frame this added sugar to make it more palatable to parents who are trying to feed their children healthy diets?

Despite the general conclusion that adding sugar to vegetables may encourage young children to eat them, even the ratings by adults were not overwhelmingly improved by the added sugar. For broccoli and kale purées both 1% and 2% sugar increased overall liking. For spinach the 2% sugar (but not the 1%) increased overall liking. For broccoli and spinach the sugar increased the ratings of liking from disliked to liked. However, for kale, even at the highest sugar level ratings never rose above the midpoint (i.e. neither like nor dislike). So, these adults did not like any of the green vegetables to begin with (at least not in puréed form) but after adding higher quantities of sugar they liked the spinach, and even with the smaller quantity of added sugar they liked the broccoli. But neither amount of sugar was enough to get them to like the kale. Would babies have different initial reactions to these vegetables? Would the addition of sugar cause them to change these reactions? I don’t know and I don’t think anyone can say based on the results of this study alone.

Just for fun, I took a look at the funding sources for the study after I finished reading it. Can you guess what one of the funding organizations was? If you guess the Sugar Association you’d be correct. I think this explains a lot because honestly I was a bit baffled as to why anyone would be looking into adding sugar to get babies to eat vegetables and why such tenuous conclusions would be drawn and publicized based on the actual findings. But who other than the Sugar Association would think that we need to encourage babies to eat more sugar?

I think a better analogy than the sugar sweetened coffee for this research would be the argument that chocolate milk is a good way to get kids to drink milk or that baking apples into a pie is a good way to encourage fruit consumption. In some ways it’s even worse because infants are at the mercy of their caregivers when it comes to what foods are offered to them and encouraging a preference for only sweet foods at such a young impressionable age could have long lasting implications for their food choices and health throughout their lives.

Continuing on with my ranting discussion about food security, I can’t help but comment on a study out of England that was getting huge media attention over the past couple of weeks. The study showed that “pound for pound” it was less expensive to eat healthy foods than to eat ultra-processed foods. The majority of the news stories concluded that poor people could be eating healthfully they just prefer to pay more for “taste and convenience”, according to one of the study’s authors. To which I say, check your privilege.

As I’ve said before, food insecurity is not a matter of simple math. While there are certainly myriad factors that contribute to our decisions about what to eat, lack of income is the root cause of food insecurity. Dismissing money as a concern on the basis of this study is wishful thinking more than anything. It’s also an insult to people who are struggling to make ends meet and feed themselves and their families.

Because some researchers went to the store and found that a pound of carrots is cheaper than a pound of french fries, the logical conclusion is that everyone should be able to afford to eat nutritious meals prepared from minimally processed ingredients? That seems like quite the leap to me. There’s no accounting for calories or ease of preparation in this comparison. Sure, a pound of vegetables may be less expensive than a pound of frozen ready-meals but I think that most people would agree that carrots do not make a balanced meal on their own. To make a nutritionally balanced meal, you’d need to round those carrots out with some dark green leafy veg, some protein like meat, fish, beans, or tofu (the authors acknowledge that meat and fish are the exception to their affordability rule), and a grain such as rice, quinoa, or whole grain bread. As most of these items need to be purchased in quantities greater than those needed for a single meal, it can quickly become more expensive to buy ingredients for a home cooked meal than it is to buy something already, or nearly, prepared. Yes, pound for pound, a bag of rice will be less expensive than frozen dinners but a bag of rice doesn’t make for much of a meal.

Stop trying to use your research to “prove” that poor people are choosing to feed their children junk. Take a good hard look at your own privilege and ask yourself how you can make this a more equitable society in which we try to help those who are struggling rather than shaming and blaming them.

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After I wrote about the study that supposedly showed that consumption of vegetables and fruit has no bearing on cancer development someone commented on facebook that I was undermining “real science” and supporting pseudo-science hacks. I think this raises an important issue when it comes to science and faith.

You see, while I am a supporter of science and detractor of pseudo-science, science is not my religion. I think that holding blind faith in anything is dangerous. Scientific research is hugely important but that doesn’t mean that every piece of research should be taken as gospel. Scientific studies can be flawed, they can be weak, they can be biased, and they can just plain be wrong. That doesn’t mean that we should ignore all scientific studies. It means that we should look at research critically. Whenever possible, we should look at larger bodies of research, rather than single studies, to draw stronger conclusions. We should look at research critically in order to base our decisions, beliefs, and advice on the best possible evidence.

Science is not infallible. That doesn’t mean that we ignore it. It just means that we need to examine it closely before deciding whether or not we accept results and conclusions drawn. Always question things. Be skeptical.

Rather than thinking that being critical of any piece of scientific research is on-par with supporting pseudo-science and quackery, we should think of blindly accepting the results of every piece of scientific research as being on-par with blindly accepting the advice of celebs and self-styled wellness gurus.